计算 .plist 字典项数（iOS SDK）
这就是 plist 的原始样子：
{
authorLastName = Doe;
authorFirstName = Jane;
imageFilePath = "NoImage.png";
title = "Account Test 1";
year = 2009;
},
{
authorLastName = Doe;
authorFirstName = John;
imageFilePath = "NoImage.png";
title = "Account Test 2";
year = 2009;
},
我想计算 plist 的总项目数，并将它们显示为：“4 个帐户”。
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *myPlistPath = [documentsDirectory
stringByAppendingPathComponent:@"Accounts.plist"];
NSDictionary *plistDict = [[NSDictionary alloc] initWithContentsOfFile:myPlistPath];
NSArray *array = [[plistDict objectForKey:0]
sortedArrayUsingSelector:@selector(compare:)];
return([NSString stringWithFormat:@"%d Accounts", [array count]]);
但是，结果返回 0。我希望它返回字典中的项目数量。
This is what the plist looks like raw:
{
authorLastName = Doe;
authorFirstName = Jane;
imageFilePath = "NoImage.png";
title = "Account Test 1";
year = 2009;
},
{
authorLastName = Doe;
authorFirstName = John;
imageFilePath = "NoImage.png";
title = "Account Test 2";
year = 2009;
},
I want to count the total items of a plist, and display them like: '4 Accounts'.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *myPlistPath = [documentsDirectory
stringByAppendingPathComponent:@"Accounts.plist"];
NSDictionary *plistDict = [[NSDictionary alloc] initWithContentsOfFile:myPlistPath];
NSArray *array = [[plistDict objectForKey:0]
sortedArrayUsingSelector:@selector(compare:)];
return([NSString stringWithFormat:@"%d Accounts", [array count]]);
However, the result returns 0. I want it to return the ammount of items in the dictionary.
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评论（3）
您的 return 语句正在转发字典第一个元素中的项目数，而不是字典本身的项目数。相反，我认为你想要的是这样的：
Your return statement is relaying the number of items in the first element of the dictionary, not the number of items of the dictionary itself. Instead what I think what you want is something like:
这似乎是旧的 OpenStep 属性列表，支持只读格式。
您的代码看起来不错，只是
NSDictionary仅将对象作为键，因此“[plistDict objectForKey:0]”不会执行您期望的操作。如果您知道属性列表的顶层是一个数组，请将其分配给NSArray，而不是NSDictionary。如果它实际上是一个字典，请使用字符串值作为键，而不是 0。That appears to be an old OpenStep property list, which is supported as a read-only format.
Your code looks okay, except that
NSDictionaryonly takes objects as keys, so "[plistDict objectForKey:0]" is not going to do what you expect. If you know the top level of your property list is an array, then assign it to anNSArray, rather than anNSDictionary. If it's actually a dictionary, use a string value for the key, rather than 0.[plistDict count]怎么样？由于您将0作为字典的键传递，因此您将无法返回任何内容，因为您不能使用nil作为键或值。What about
[plistDict count]? Since you're passing in0as the key to the dictionary you won't get anything back since you can't usenilas a key or a value.